This application claims the priority of Japanese Patent Application No. 2000-229661 filed on Jul. 28, 2000, which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an illumination apparatus and a projection type display apparatus using the same; and, in particular, to improvements in a projection type display apparatus which projects an image under magnification by using a transmission type or reflection type liquid crystal display device or a digital micromirror device (DMD) and in an illumination apparatus mounted in the projection type display apparatus.
2. Description of the Prior Art
As the projection type display apparatus, one using a transmission type or reflection type liquid crystal display device, for example, has been well known. Also, DMDs have been put into use in recent years.
On the other hand, there has been a strong demand for making the projection type display apparatus further compact. Therefore, in order to reduce the number of light valves such as liquid crystal display devices, one employing a color sequence technique has been known (e.g., Japanese Patent Publication No. 2939237).
FIG. 8 shows the configuration of a conventional projection type display apparatus having such a color sequence type technique introduced therein and using a reflection type liquid crystal display device.
The projection type display apparatus in accordance with this prior art comprises a light source section 101 composed of an illuminant 111 and a reflector 112; a color wheel section 103 in which a disk 132 for selectively transmitting therethrough a predetermined wavelength of light in a luminous flux emitted from the light source section 101 is rotatable by a rotary motor 131; a rod integrator 102 for mixing color light components selected by and transmitted through the color wheel section 103 in order to homogenize the light quantity distribution; a convergent lens 122; a collimator lens 124; a polarizing beam splitter 160 for deflecting the incident light at a polarizing surface 161; a reflection type liquid crystal display device 140 for selectively reflecting incident light so as to generate a color light component carrying image information; and a projection lens 170 for projecting the color light component carrying the image information onto a screen which is not depicted.
Also known is one using a flyeye integrator in place of the above-mentioned rod integrator 102 (e.g., Japanese Patent Publication No. 2939237). In this prior art, the illumination efficiency can be prevented from deteriorating due to the use of a rod integrator, uneven illumination can be kept from occurring due to dust attached to a rod end face or unevenness in coating thereof, and so forth.
Since the light source section, the integrator, and the liquid crystal display device (light valve) are disposed substantially linearly in any of the above-mentioned prior art, they are hard to accommodate within the apparatus housing compactly. Though the optical system can be constructed three-dimensionally if a mirror member is used for bending the optical path, separately providing the mirror member necessitates a space for placing the same and raises the cost. In particular, it is difficult for a mirror member to be disposed separately in a region extending from the light source section to the integrator, so that there is substantially no freedom in design for arranging the optical system, which has been a large obstacle to make the apparatus compact.
In the case where a mirror member is separately provided as mentioned above so as to three-dimensionally bend the optical path between the integrator section and the liquid crystal display device (light valve), the illumination area rotates on the liquid crystal display device (light valve), which is problematic.
Since the current projection type display apparatus is aimed at delicately arranging individual members of the optical axis so as to utilize the space within the apparatus as efficiently as possible, there has been an urgent necessity to clear the obstacles mentioned above.
In view of such circumstances, it is an object of the present invention to provide an illumination apparatus employing a color sequence technique, improving the freedom of design from the light source section to the integrator, and achieving a three-dimensional construction of the optical system without separately providing a reflection member, whereby the apparatus can be made compact at a lower cost without generating problems such as the rotation of the illumination area; and a projection type display apparatus using the same.
The present invention provides an illumination apparatus comprising:
a light source section constituted by an illuminant and a light converging portion for converging a luminous flux from the illuminant;
a color reflector comprising a rotary reflecting member disposed at a position where the luminous flux from the light source section is converged, the rotary reflecting member reflecting only a specific wavelength component in the luminous flux according to an angle of rotation from a reference position; and
light quantity homogenizing means for homogenizing a light quantity of the luminous flux reflected by the color reflector.
Preferably, the color reflector comprises n areas separately formed in a circumferential direction, each area being formed with a reflecting surface for reflecting only a predetermined specific wavelength component in the luminous flux, whereas the luminous flux from the light source section successively irradiates the reflecting surfaces.
The reflecting surfaces are formed in the respective areas on the color reflector such that center angle regions of the reflecting surfaces reflecting only the predetermined specific wavelength component have substantially the same size.
The n may be 3, whereas the reflecting surfaces may comprise a red light reflecting surface, a green light reflecting surface, and a blue light reflecting surface.
On the color reflector, the green light reflecting surface may be formed with a center angle region greater than that of each of the other reflecting surfaces.
Preferably, the light quantity homogenizing means is constituted by a pair of flyeye lens members.
An axis of rotation of the color reflector and a normal on each reflecting surface may be either substantially parallel to each other or substantially perpendicular to each other.
The color reflector may have a polygonal cross section perpendicular to an axis of rotation, whereas the reflecting surfaces are successively formed at a side face portion.
The polygonal cross section may be a regular polygon.
The reflecting surface may be formed from a dichroic film. Also, the reflecting surface may be formed from a diffraction grating or hologram.
The present invention provides a projection type display apparatus comprising:
the illumination apparatus mentioned above;
a light valve for modulating output light from the light quantity homogenizing means according to a predetermined image signal; and
a projection lens for projecting an optical image formed by the light modulated by the light valve onto a screen.
When a single light valve is used, the apparatus can be made more compact.